Pneumatic power file



Jan. 26, 1954 c. T. SKILLMAN PNEUMATIC POWER FILE 3 Sheets-Sheet 1 Filed Dec. 27, 1949 Inventor n Claude 7'. Stillman Jan. 26, 1954 c. T. SKILLMAN PNEUMATIC POWER FILE 3 Sheets-Sheet 2 Filed Dec. 27, 1949 Claude 7i Ski/Iman Fig.

lure/[tor Patented Jan. 26, 1954 PNEUMATIC POWER FILE Claude T. Skillman,

of fifty per cent Maria, Calif.

Santa Maria, Calif., assignmto William K.

March, Santa Application December 27, 1949, Serial N 0. 135,195

7 Claims.

The present invention relates to new and useful improvements in power files, and more particularly pertains to a fluid pressure actuated file having improved means for controlling the reciprocation of the piston rod and for adjustably holding the file.

The primary object of this invention is to provide a power file which will eificiently perform the filing operation while requiring a minimum amount of time and efiort on the part of the operator.

Another important object of this invention is to provide a power file in accordance with the foregoing object which may be adjusted to file arcuate surfaces and surfaces inclined to the horizontal.

Another important object of this invention in conformity with the foregoing objects is to provide a, power file in which the length of the stroke of the file and its speed of oscillation is adjustable.

Another important object of this invention is to provide a power file of this character, which utilizes a fiuid pressure cylinder, and in which the fluid pressure cylinder is guidingly supported relative to the file so as to avoid undue vibration and stresses in the same.

Still another object is to provide a device of this character of simple and practical construction, which is efficient and reliable in operation, relatively inexpensive to manufacture, and otherwise well adapted for the purposes for which the same is intended.

A meritorious feature of this invention resides in the means provided for engaging the file, which will permit the same to be angularly adjusted relative to the power cylinder as well as flexed for filing arcuate surfaces.

Another important feature of the present invention resides in the triple function of the guide rod, that is, forming a pivot for the angular adjustment of the file, adjusting the amount of flexing of the file, and guiding and supporting the power cylinder.

A final important feature to be specifically enumerated herein resides in the means provided for reciprocating the piston rod which includes a pair of rotary valves, which are adjustable to vary the length of the stroke of the file, and further valve means provided for controlling the rate of reciprocation of the piston rod.

These, together with various ancillary features and objects of the invention which will later become apparent as the following description .vention, portions of the assembly being shown proceeds, are attained by the present invention, the principles of which have been illustrated by way of example only in the accompanying drawings, wherein:

Figure l is a side elevational view of the present invention;

Figure 2 is a top plan view of the present incylinder being broken away to show the internal construction of the same;

Figure 3 is a front elevational view of the present invention, the angle through which the body portion may be angularly adjusted being indicated in dash lines;

Figure 4 is a vertical transverse sectional view of the present invention, being taken upon the plane of the section line 44 of Figure 1;

Figure 5 is a vertical longitudinal sectional view of the present invention, being taken upon the plane of the section line 5-5 of Figure 2;

Figure 6 is a side elevational view similar to that shown in Figure 1, with the concealed portion of the piston rod and the piston being indicated in dotted outline and the rotary valve in vertical section to illustrate the internal construction of the same;

Figure 7 is a side elevational detail view illustrating the manner by which the file is flexed;

Figure 8 is a. vertical transverse sectional view of the present invention, being taken substantially upon the plane of the broken section line 88 in Figure 1;

Figure 9 is a vertical longitudinal detail sectional view that is enlarged and taken upon the plane of the section line 9-9 of Figure 2;

Figure 10 is an enlarged vertical transverse sectional view taken upon the plane of the line l0-l0 of Figure 1; and

Figure 11 is an exploded perspective detail view of the means provided for adjusting the length of the piston rod stroke.

Reference is now made more specifically to the accompanying drawings, wherein like numerals designate similar parts throughout the various views, and in which the pneumatic power file is indicated generally by the numeral In.

The pneumatic power file IE1 comprises an integral body formed with a cylinder l2 atone end and a handle Id at the other, the cylinder [2 being closed at one end with an integral head wall l6 and at the other end by a cylinder head l8 threadingly engaging the outer end of the cylinder 12. A piston 20 is slidably disposed in the cylinder l2 and threadingly receives piston rods 22 and 24.

As will be clearly seen in Figure 5, the inner ends of the piston rods 22 and 24 are shouldered to hold the retaining rings 26 and packing members 28 against opposite faces of the piston 20, while the piston rods extend through the cylinder heads I8 and I6, respectively.

Means is provided to reciprocate the piston in the cylinder I2. These means include a passage 30 inthe handle I4, which, through a 'suit-' able coupling 29, at the rear of the handle I4, communicates with an air hose 32. The handle I4 includes a sliding valve 34 as a part..of..the hand grip 36, which is adapted to open'and 'close the passage 30. As clearly shown inFigure 5, the hand grip 36 includes. a spring 40 which. yieldingly urges the sliding valve 34 to a position closing the passage 30, but which is depressed upon squeezing the hand grip 36 to slide the valve 34 to a position opening the passage 30-as will be readily understood. As best shown in Figures 5 and 10, the maximum amount of-air permitted to flow in the passage 30 is adjustably controlled by the needle valve assembly indicated generally at 42. The needle valve'44 threadingly extends into a transverse bore 46 communicating with the passage 30, and which is provided at its outer extremity with a knurled knob-48 to facilitate turning of the same, and which is retained friction-ally in adjusted relation by means of a compression spring 50.

Themeans to reciprocate the piston 20 further includes a rotary valve assembly 52 disposed to one side of the cylinder 2; The assembly 52 comprises a valve housing 5 5 preferably formed integrally with the cylinder I2, and in which is seated for rotation valve plugs 56 and 58. The rotary valve plugs 56 and 58 each communicates through a T-shaped passage 56 in the valve housing 54 and conduit 62 with the passage 30. The space in which the rotary valve plugs 56 and 58 are disposed further communicates through conduits 64 and 66, respectively, with opposite ends of the cylinder I2, L-shaped passages 68 and 10 being provided in the heads I8 andl6, respectively, for this purpose.

As may be readily understood upon reference to Figure 6, the rotary valve cores 56 and 58 are provided with openings I2 and 14 and the valve housing 54 provided with exhaust ports 16 and 18, the openings in the rotary valve plugs being of such a shape that the plugs maybe rotated from one position affording communication between the conduit 62 and the interior of the cylinder I2 and another position providing com munication between I2 "and the exhaust ports, Thus, it will be seen that air may beforced into one end of the cylinder I2 and exhausted from the other'endalternatively by the use of thevalve assembly '52 so as to'cause the piston 20' and the p'istonrods 22 and 24 to reciprocate.

The rotary valve plugs and 58 are rotated to reciprocate the piston 20 by means which'include crank arms and 82 which are connected to the 'valve plugs and disposed outside "of the" valve cover plate 84. The crank arms '80 and 82 are connected by a cross link 86'forsimultaneous and synchronous actuation of 'thevalve plugs upon rotation of either of the crankarms 80 or 82. A valve actuating member 88 is disposed laterally of the cylinder I2 which includes a transverse arm 90 at one end thereof whichterminates-in acollar 92 slidably. embracing the piston rod 22,- the collar '92 being adjustablyretamed on the piston rod 22 bymeansxloi a' set.

the interior of the cylinder slot 96 and slots H2 in 82, whichare adapted end'IMof thestops 9B theistopsf98 and I00 screw 94 in the collar. The member 88 is provided with a longitudinal slot 96 in which are adjustably positioned stops 96 and I00. Each of the stops 98 and I00 comprises a slide I02 having a medial rib I04 disposed to slide in the slot 96, and a threaded projection I06 extending from the rib I04 engaged by a knurled nut I08. It will be understood that tightening of the nut I08 clamps the rib I04 in adjusted relation in the slot 96. Floating pins IIO extend through the the crank arms 80 and to engage the concaved and I00.

' The operation .of the piston reciprocating means willzbexr'eadily understood. Since the member 88: is connected to the piston rod 22, it

.will move therewith, the length of the stroke of the piston being determined by the spacing of which strike the floating pins III) to actuate the valve plugs 56 and 58 for reversing the direction of travel. Accordingly, the length of the piston stroke maybe shortened by moving the stops toward each other or extended by moving them apart, and when-the piston stroke is short, the motion of the piston 20 may be confined to any predetermined portion of the cylinder I2 by either moving the stops 98- and- I00 inwardly or outwardly on the member 88, or adjusting the collar 92 longitudinally on the piston rod 22 as will be understood. The importance of the degree of control held over the motion of the piston 20, thatris, as to controlling the amplitude of its motion, restricting its motion to a selected portion of the cylinder I2, and controlling its velocityby means of the needle valve 44, will be more fully appreciated hereinafter.

The opposite outer ends of the iston rods 22 an -24 are flattened and pivoted by fasteners I I6 to the bifurcated end of links H8, the other ends of the links H8 are pivotally received between bifurcated ends of eye members I20, the eye members I20 being rotatably interdigitated with a member I22, which is in turn pivoted by a fastener I24 between upstanding ears I26 on a flexible tool holder plate I28. A guide rod I30 extends through the interdigitated portions of the members I20 and I22 and constitutes a pivotal connection therebetween. A file I3I is secured to the member I20 by having upstanding threaded studs I32 thereon extending through the plate I28 and engagedby nuts I34, as best shown in Figure 9.

The opposite'ends of the rod I30 are threaded and provided with wing nutslI36 which cooperate with stop nuts I38 to retain the members I20 and I22, which maybe convenientlytermed tool holders, in-'-adjusted angular relationship, whereby the handle I4 and cylinder I2 may be adjusted angularly with respect to the plate I28 and file as indicated by. the arrows I40 inFigure 3.

Means isprovided to stabilize the power file I0, guide the movement of the rod' I 30, and lend support" to the" cylinder I2- 'and handle I4, which includes a p'airof rollers-I42 carried by the-cylinder' I2 and engaging outer peripheries of the rollers I42 are concavedfor engagement with the guiderod I30 and therollers are journaled between pairs of lugs I44 depending from the cylinder I2.

An important function of the present invention residesiin the factthat the wing 'nuts I36 may i be moved towa'rd'v each other "on the guide 753rod -I 30', whereby .theiplate I28 and'thefile I3I the guide rod'l30. The

may be forced to flex upwardly or downwardly as desired, the pivotal connections between the plate 128 and the piston rods permitting the file l3! to flex smoothly throughout its entire length as indicated in Figure 7. To retain the guide rod 130 in proper engagement with the rollers 142 when the file is in flexed condition, the lower ends of the links H 8 which receive the pivot fastener I46 are slotted, as at 148, to compensate for the vertical displacement of the guide rod I30 during flexing of the file I31, it being noted that the pivot fastener M6 may be of a type that, upon tightening, retains the link I48 and the member I26 in adjusted relationship.

The advantages of the pneumatic power file disclosed herein will be readily appreciated. The paramount advantages flowing from the disclosed construction reside in the extreme flexibility of the machine, in that the file may be arcuately flexed or angularly adjusted relative to the handle 14, each of these adjustments being possible independently or simultaneously. The utility of the device is further enhanced by the extreme flexibility of control furnished over the motion of the file [31 which has been emphasized hereinbefore, it being noted that short strokes of the file are frequently desired when working on a plane surface but highly desirable when working on arcuate surfaces.

From the foregoing, the construction and operation of the invention will be readily understood and further explanation is believed to be unnecessary. However, since numerous modifications and changes will readily occur to those skilled in the art after consideration of the foregoing specification and accompanying drawings, it is not desired to limit the invention to the exact construction shown and described, but all suitable modifications and equivalents may be resorted to, falling within the scope of the appended claims.

Having described the invention, as new is:

l. A fluid pressure actuated tool, comprising a cylinder, a piston rod and projecting from the opposite ends of said cylinder, means for imparting reciprocatory motion to said piston rod, a cutting element disposed laterally from said cylinder, means which what is claimed include a pivotal connection carried at each end of the piston rod for engaging the cutting element, a guide rod disposed in parallel relation to said cylinder and connecting said last means and constituting the pivot for said pivotal connections, means carried by said cylinder and engaging said guide rod for guiding and supporting said cylinder relative to said cutting element.

2. The combination of claim 1, wherein said means for imparting reciprocatory motion includes a pair of rotary valves responsive to motion of the piston rod for actuation, and means operatively associated with the valves for adjusting the stroke of the piston rod.

3. A fluid pressure actuated tool, comprising a cylinder, a piston rod slidably extending through said cylinder, means for imparting reciprocatory motion to said piston rod, a flexible cutting element disposed laterally from said cylinder, a pair of tool holders each having one end pivotally connected to the cutting element, a pair slidably extending through v operating with said guide rod of links each having one end pivoted to opposite ends of said piston rod and the other end pivoted to one of said tool holders, a guide rod adjustably connecting said tool holders for flexing the cutting element, and means carried by said cylinder and engaging said guide rod for guiding and supporting said cylinder relative to said cutting element.

4. A power tool comprising a double-ended cylinder, a piston rod extending through said cylinder, valve means controlling the flow of actuating fluid into said cylinder, articulated links pivotally mounted at each end of said piston rod, tool holders transversely interdigited with said links, a guide rod extending through and connecting said tool holders to said links.

5. A power tool comprising a double-ended cylinder, a piston rod extending through said cylinder, valve means controlling the flow of actuating fluid into said cylinder, articulated links pivotally mounted at each end of said piston rod, tool holders transversely interdigited with said links, a guide rod extending through and connecting said tool holders to said links, adjusting means coto determine the spacing of said tool holders.

6. A power tool comprising a double-ended cylinder, a piston rod extending through said cylinder, valve means controlling the flow of actuating fluid into said cylinder, articulated links pivotally mounted at each end of said piston rod, tool holders transversely interdigited with said links, a guide rod extending through and connecting said tool holders to said links, bearing guides on said cylinder, said guide rod being seated in said bearing guides.

7. A power tool comprising a double-ended cylinder, a piston rod extending through said cylinder, valve means controlling the flow of actuating fluid into said cylinder, articulated links pivotally mounted at each end of said piston rod, tool holders transversely interdigited with said links, a guide rod extending through and connecting said tool holders to said links bearing guides on said cylinder, said guide rod being seated in said bearing guides, said articulated links including a pin and slot joint.

CLAUDE T. SKILLMAN.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 747,766 Reed Dec. 22, 1903 984,112 Schumacker Feb. 14, 1911 1,000,159 Dukes Aug. 8, 1911 1,136,796 Hammer Apr. 20, 1915 1,206,638 Blum Nov. 28, 1916 1,276,167 Brown Aug. 20, 1918 1,305,283 Heckmann June 3, 1919 1,631,743 Lipscomb June 7, 1927 2,068,201 Shurtz Jan. 19, 1937 2,102,782 Wren Dec. 21,1937 2,120,300 Taylor June 14, 1938 2,127,176 Kroecker Aug. 16, 1938 2,182,289 Eisenhohr Dec. 5, 1939 2,214,189 Ahlskog Sept. 10, 1940 2,224,132 Barnes Dec. 10, 1940 2,255,395 Spink Sept. 9, 1941 2,446,011 Johnson et a1. July 27, 1948 

